1. Field of the Invention
The present invention relates to digital mobile communication field, specifically relates to a service transmitting method of mobile multimedia broadcasting network.
2. Description of Related Art
In recent years, technologies and standards of digital mobile multimedia broadcasting have developed rapidly, such as DVB-H (Digital Video Broadcast Handheld) of Europe, Media FLO (Media Forward Link Only) of the USA, CMMB (China Mobile Multimedia Broadcast) of China and so on.
Compared with analog technologies, one of the advantages of the digital mobile multimedia broadcasting network is that a broadcasting channel can support transmissions of a plurality of services by multiplexing on the premise of satisfying the requirements on service qualities so that the utilization efficiency of radio resource can be greatly increased. We call the data obtained by multiplexing of a plurality of services within a certain time a broadcast frame. For the receiving terminal, as there are a plurality of services on a broadcast frame, the terminal needs information which we call multiplexing configuration information and can exactly describe the broadcast channel resource each service used in the present broadcast frame to receive one or more services needed rapidly and exactly. Multiplexing configuration information is generated by the sending terminal when multiplexing occurs and is sent to the terminal in one same broadcast frame.
In consideration of reducing the receiving power consumption of a mobile multimedia receiving terminal, all mobile multimedia broadcasting technologies have adopted various methods to reduce the working time of the receiving terminal. In addition to service data compression, another two methods are also widely used:
Time slicing technology, in which a broadcast frame is further divided into a plurality of time slices and one time slice only bears one service, thus the receiving terminal only needs to receive the time slice needed and needless to receive the whole broadcast frame, if only needing to receive one service.
Multiplexing configuration information and service data use different time slices, so as to reduce the number of spending information in service data or in other words to increase the proportion of services payload data on time slices, so that lengths of time slices can be further reduced, which leads to reducing of the working time of the receiving terminal.
There are many design methods for broadcast frames used by various mobile multimedia broadcasting technologies, but basic constitutions of broadcast frames are similar.
We call the time slice in which multiplexing configuration information is located multiplexing information time slice and the time slice in which a service is located service time slice. In this manner, the receiving terminal can receive the service needed normally only by acquiring the multiplexing information time slice and the service time slice needed in each frame. If the times of reading spending time slices by the receiving terminal can be reduced, the working time of the receiving terminal can also be further reduced so that the design of mobile multimedia broadcasting system can have a better feature of current saving. Various mobile multimedia broadcasting technologies have designs for this point. Below are two common methods:
Method A: adding interval time indication information in the service time slice, the information used to indicate the time when the next service time slice of the present service appears. This technology has been applied in DVB-H system. The problem of this method is that when a broadcast frame bears services having variable rate, each interval time may be varied and the receiving terminal needs to acquire interval time indication information from each service time slice no matter whether data rate of the service currently received by the receiving terminal is variable or not.
Method B: auxiliary multiplexing information with a fixed length is added in the service time slice, for a broadcast frame has a fixed time length (such as 1 sec.). Whether multiplexing configuration information of the present service will be changed in the next frame and corresponding multiplexing configuration information or filling are provided in the auxiliary multiplexing information, according to which the receiving terminal can receive the service needed. Only when needing to receive other services, the receiving terminal needs to receive the multiplexing information time slice. However, this method also has a problem of increasing the processing complexity of the receiving terminal.
For a mobile multimedia broadcasting network, the services most commonly used by users are the real-time services which are continuously broadcasted such as television and audio broadcast. The feature of this kind of service in the broadcasting process is that the average data rate can be considered to be fixed and as long as the coverage area or service quality is not adjusted by broadcast operator, the broadcast channel resource (the size of time slice) needed by this kind of service can also be fixed.
If this kind of service application is prevailing, the existing methods not only increase additional spending but the procedure of receiving processing of the receiving terminal is also relatively complex.